1. Field of the Invention
The present invention relates to a friction clutch assembly, especially for a motor vehicle.
2. Description of Related Art
More particularly, the invention relates to a clutch of the pull to release type, one embodiment of which is described and shown in the document FR-A-2 304 826.
Such a type of clutch includes a friction disc which is fixed releasably to, but for rotation with, a rotatable drive shaft, a control member which is adapted to control the disengagement of the friction disc from the drive shaft when an axial tractive force is exerted on it, and a clutch release bearing which is arranged to work axially in traction on the control member of the clutch.
Such a clutch, as is disclosed in the document FR-A-2 304 826, may be of the mechanically controlled type, that is to say of the type that includes a declutching control fork which is made in the form of a lever pivoted on the clutch casing, and of which the inner end works axially on a sliding sleeve, one end of which is coupled axially, for example, to the outer ring of the rolling bearing which is part of the clutch release bearing.
As is disclosed in that document, the use of the mechanical declutching control fork in a direction opposite to that which produces disengagement of the clutch, enables fastening in axial traction to be obtained, during assembly of the engine unit, between an element which is coupled to the inner ring of the rolling bearing of the clutch release bearing and an actuating member which is engaged with the declutching levers or diaphragm that form part of the clutch, this fastening being obtained by a resilient mating effect which may also be referred to as clipping.
Various different designs of clutch are also known which include a hydraulic actuating device that comprises at least one actuating piston, one end of which works on the clutch release bearing in order to urge the clutch release bearing axially in a first direction, so as to disengage the clutch when the hydraulic actuating device is supplied with fluid from a source of fluid under pressure, such as for example a clutch cylinder.
One example of such a hydraulically actuated clutch is described and shown in the document U.S. Pat. No. 3,955,660, in which the actuating piston is made in the form of a cylindrical sleeve, which is mounted for sliding movement on a cylindrical guide surface fixed to the clutch casing.
Such a type of hydraulically actuated clutch, which no longer has any mechanical fork for actuating the clutch release bearing, does not enable initial fastening to be obtained by resilient clipping effect between the output member of the clutch release bearing and the actuating member.